[Bug-gnubg] None

Either I stumbled upon a bug or (more likely) my understanding of the cube
analysis is lacking. Here is the situation:

1. I am an running a March 2 build on Windows NT
2. gnubg has already borne off two checkers

3. gnubg has one checker on the bar, trapped behind my 6-prime extending
from my 2 pt through my seven point

4. The cube is at 2 and I own it.
5. I am on roll.

Looking at this situation in analysis afterwards, I wanted to see when/if I
should have doubled. I clicked on the Cube decision tab. Clearly I think I
should double as a) I can't gammon gnubg, b) if I play on, I could possibly
lose should gnubg start rolling doubles once I open up, c) gnubg will
clearly pass on a cube at this moment, d) the possibility that my situation
will erode sufficiently such that I would both double gnubg and gnubg will
accept, enabling me to win a game for 4 points I feel are infinitesimally
small (though not zero) - I believe I will likely close him out and then win
the bear off race once gnubg gets in.

My question is: Given that there is still contact possible, why is option 3
(No double) given a +1.000. I feel it should be some quantity less than
1.000 as a win for me is certainly not guaranteed should I not double. My
interpretation of this is, you may either double and win 1.000 at this
instant or don't double and still win 1.000. With contact still possible,
should it really be rated 1.000?